Thanks to anyone who gave advice
This is what I have done so far, and when I exported it to the Android platform to run it, any mp3 file selected would not play.
I went through the text to make sure the music was selected correctly and the event was triggered correctly.
+ FileChooser: On changed
----+ System: FileChooser.FileTypeAt(0) = "audio/mpeg"
-----> Audio: Add remote URL FileChooser.FileURLAt(0) (type "audio/mpeg") as name "LocalMusic"
-----> Audio: Play FileChooser.FileURLAt(0) looping from Music at 10 dB (stereo pan 0, tag "")
-----> Text4: Set text to 1
+ System: Every tick
-> Text: Set text to FileChooser.FileTypeAt(0)
-> Text2: Set text to FileChooser.FileNameAt(0)
-> Text3: Set text to FileChooser.FileURLAt(0)